Field of the Invention
Embodiments of the present invention relate generally to structures and methods for detecting materials, including explosives or contraband, using a terahertz (THz) fingerprint.
Background of the Invention
Explosive materials exhibit a distinct THz fingerprint in the terahertz (THz) frequency range that offers a unique characteristic for discrimination and detection. Detecting this signature would allow for detection of such materials that may be hidden in luggage, the body or elsewhere. In addition, THz imaging offers the promise of a nonintrusive technique to detect contraband hidden on the human body.
However, current THz spectrometer systems have limited performance in a stand-alone detection mode of operation. Moreover, they are not able to penetrate high water content media, such as the human body. Even frequencies in the near infrared (NIR) band do not provide a solution because skin and outer layer materials (e.g., clothing) are likely to be opaque to infrared radiation.
Conventional THz detection systems rely on broad-band detectors to detect THz radiation. Typically, they require mechanically tunable interferometers to achieve spectral resolution. To achieve the required sensitivity, conventional THz detectors also require cooling to liquid helium temperatures. While THz spectrometer systems exist, they are too bulky and fragile for field applications.
Thus, there is a need to provide data analysis methods and detection/discrimination processes to identify and classify threats and to reduce false alarms.